Method and apparatus for sending scheduling information for broadcast and multicast services in a cellular communication system

ABSTRACT

Techniques for supporting broadcast, multicast, and unicast services in a cellular system are described. A Node B may multiplex data for broadcast and multicast services and data for unicast services on radio resources available for transmission. The Node B may periodically send scheduling information used to determine the radio resources carrying the broadcast and multicast services. In one design, the Node B may time division multiplex the data for the broadcast and multicast services and the data for the unicast services. The scheduling information may convey time unit(s) used for each broadcast or multicast service. In another design, the Node B may map the data for the broadcast and multicast services to time frequency blocks. The scheduling information may (i) convey the time frequency block(s) used for each broadcast or multicast service or (ii) point to control information conveying the time frequency block(s) used for each service.

The present application is a continuation of U.S. application Ser. No.12/128,972, entitled “METHOD AND APPARATUS FOR SENDING SCHEDULINGINFORMATION FOR BROADCAST AND MULTICAST SERVICES IN A CELLULARCOMMUNICATION SYSTEM”, filed on May 29, 2008, which in turn claimspriority to provisional U.S. Application Ser. No. 60/940,873, entitled“A SCHEDULING SCHEME FOR E-MBMS,” filed May 30, 2007, each of which isassigned to the assignee hereof and incorporated herein by reference inits entirety.

BACKGROUND

I. Field

The present disclosure relates generally to communication, and morespecifically to techniques for supporting broadcast and multicastservices in a cellular communication system.

II. Background

A cellular communication system can support bi-directional communicationfor multiple users by sharing the available system resources. Cellularsystems are different from broadcast systems that can mainly or onlysupport uni-directional transmission from broadcast stations to users.Cellular systems are widely deployed to provide various communicationservices and may be multiple-access systems such as Code DivisionMultiple Access (CDMA) systems, Time Division Multiple Access (TDMA)systems, Frequency Division Multiple Access (FDMA) systems, OrthogonalFDMA (OFDMA) systems, Single-Carrier FDMA (SC-FDMA) systems, etc.

A cellular system may support broadcast, multicast, and unicastservices. A broadcast service is a service that may be received by allusers, e.g., news broadcast. A multicast service is a service that maybe received by a group of users, e.g., a subscription video service. Aunicast service is a service intended for a specific user, e.g., voicecall. It is desirable to efficiently support broadcast, multicast, andunicast services in the cellular system.

SUMMARY

Techniques for supporting broadcast, multicast, and unicast services ina cellular system are described herein. In an aspect, a Node B maymultiplex data for broadcast and multicast services and data for unicastservices on radio resources available for transmission. The radioresources may comprise time, frequency, power, code, and/or otherresources usable for transmission over the air. The Node B mayperiodically send scheduling information that may be used by the usersto determine the radio resources carrying the broadcast and multicastservices. The scheduling information may convey where and possibly howthe broadcast and multicast services are sent.

In one design, the Node B may time division multiplex (TDM) the data forthe broadcast and multicast services and the data for the unicastservices. Each broadcast or multicast service may be sent in at leastone time unit, and the scheduling information may convey the timeunit(s) used for each broadcast or multicast service. In another design,the Node B may map the data for the broadcast and multicast services totime frequency blocks. The scheduling information may (i) convey thetime frequency block(s) used for each broadcast or multicast service or(ii) point to control information that may convey the time frequencyblock(s) used for each service.

The scheduling information may be sent in each scheduling period and mayconvey the radio resources used for the broadcast and multicast servicesin the current or subsequent scheduling period. The Node B may alsoperiodically send a change flag that indicates whether or not thescheduling information will change in an upcoming scheduling period.

Various aspects and features of the disclosure are described in furtherdetail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cellular communication system.

FIG. 2 shows an example transmission structure.

FIG. 3 shows example transmissions of different services in a multi-cellmode.

FIG. 4 shows example transmissions of different services in asingle-cell mode.

FIG. 5 shows a design of sending scheduling information in themulti-cell mode.

FIGS. 6 and 7 show two designs of sending scheduling information in thesingle-cell mode.

FIG. 8 shows a process for sending broadcast, multicast, and unicastservices.

FIG. 9 shows an apparatus for sending broadcast, multicast, and unicastservices.

FIG. 10 shows a process for receiving services.

FIG. 11 shows an apparatus for receiving services.

FIG. 12 shows a design of sending a change flag for schedulinginformation.

FIG. 13 shows a process for sending scheduling information.

FIG. 14 shows an apparatus for sending scheduling information.

FIG. 15 shows a process for receiving scheduling information.

FIG. 16 shows an apparatus for receiving scheduling information.

FIG. 17 shows a block diagram of a Node B and a UE.

DETAILED DESCRIPTION

The techniques described herein may be used for various cellularcommunication systems such as CDMA, TDMA, FDMA, OFDMA and SC-FDMAsystems. The terms “system” and “network” are often usedinterchangeably. A CDMA system may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA system may implement a radiotechnology such as Global System for Mobile Communications (GSM). AnOFDMA system may implement a radio technology such as Evolved UTRA(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA and E-UTRA are part ofUniversal Mobile Telecommunication System (UMTS). 3GPP Long TermEvolution (LTE) is an upcoming release of UMTS that uses E-UTRA, whichemploys OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA,UMTS, LTE and GSM are described in documents from an organization named“3rd Generation Partnership Project” (3GPP). cdma2000 and UMB aredescribed in documents from an organization named “3rd GenerationPartnership Project 2” (3GPP2). For clarity, certain aspects of thetechniques are described below for LTE, and LTE terminology is used inmuch of the description below.

FIG. 1 shows a cellular communication system 100, which may be an LTEsystem. System 100 may include a number of Node Bs and other networkentities. For simplicity, only three Node Bs 110 a, 110 b and 110 c areshown in FIG. 1. A Node B may be a fixed station used for communicatingwith the user equipments (UEs) and may also be referred to as an evolvedNode B (eNB), a base station, an access point, etc. Each Node B 110provides communication coverage for a particular geographic area 102. Toimprove system capacity, the overall coverage area of a Node B may bepartitioned into multiple smaller areas, e.g., three smaller areas 104a, 104 b and 104 c. Each smaller area may be served by a respective NodeB subsystem. In 3GPP, the term “cell” can refer to the smallest coveragearea of a Node B and/or a Node B subsystem serving this coverage area.In other systems, the term “sector” can refer to the smallest coveragearea of a base station and/or a base station subsystem serving thiscoverage area. For clarity, 3GPP concept of cell is used in thedescription below.

In the example shown in FIG. 1, each Node B 110 has three cells thatcover different geographic areas. For simplicity, FIG. 1 shows the cellsnot overlapping one another. In a practical deployment, adjacent cellstypically overlap one another at the edges, which may allow a UE toreceive coverage from one or more cells at any location as the UE movesabout the system.

UEs 120 may be dispersed throughout the system, and each UE may bestationary or mobile. A UE may also be referred to as a mobile station,a terminal, an access terminal, a subscriber unit, a station, etc. A UEmay be a cellular phone, a personal digital assistant (PDA), a wirelessmodem, a wireless communication device, a handheld device, a laptopcomputer, a cordless phone, etc. A UE may communicate with a Node B viatransmissions on the downlink and uplink. The downlink (or forward link)refers to the communication link from the Node B to the UE, and theuplink (or reverse link) refers to the communication link from the UE tothe Node B. In FIG. 1, a solid line with double arrows indicatesbi-directional communication between a Node B and a UE. A dashed linewith a single arrow indicates a UE receiving a downlink signal from aNode B, e.g., for broadcast and/or multicast services. The terms “UE”and “user” are used interchangeably herein.

FIG. 2 shows an example transmission structure 200 that may be used forthe downlink in system 100. The transmission timeline may be partitionedinto units of radio frames. Each radio frame may have a predeterminedduration (e.g., 10 milliseconds (ms)) and may be partitioned into 10subframes. Each subframe may include two slots, and each slot mayinclude a fixed or configurable number of symbol periods, e.g., six orseven symbol periods.

The system bandwidth may be partitioned into multiple (K) subcarrierswith orthogonal frequency division multiplexing (OFDM). The availabletime frequency resources may be divided into resource blocks. Eachresource block may include Q subcarriers in one slot, where Q may beequal to 12 or some other value. The available resource blocks may beused to send data, overhead information, pilot, etc.

The system may support evolved multimedia broadcast/multicast services(E-MBMS) for multiple UEs as well as unicast services for individualUEs. A service for E-MBMS may be referred to as an E-MBMS service andmay be a broadcast service or a multicast service.

In LTE, data and overhead information are processed as logical channelsat a Radio Link Control (RLC) layer. The logical channels are mapped totransport channels at a Medium Access Control (MAC) layer. The transportchannels are mapped to physical channels at a physical layer (PHY).Table 1 lists some logical channels (denoted as “L”), transport channels(denoted as “T”), and physical channels (denoted as “P”) used in LTE andprovides a short description for each channel.

TABLE 1 Channel Name Type Description Dynamic Broadcast D-BCH L Carrysystem information. Channel E-MBMS Scheduling MSCH L Carry schedulinginformation Channel and possibly control informa- tion for E-MBMSservices. E-MBMS Traffic MTCH L Carry data for E-MBMS Channel services.E-MBMS Control MCCH L Carry configuration informa- Channel tion forE-MBMS services. Multicast Channel MCH T Carry the MTCH and MCCH.Downlink Shared DL-SCH T Carry the MTCH and other Channel logicalchannels. Physical Broadcast PBCH P Carry basic system informa- Channeltion for use in acquiring the system. Physical Multicast PMCH P Carrythe MCH. Channel Physical Downlink PDSCH P Carry data for the DL-SCH.Shared Channel Physical Downlink PDCCH P Carry control informationControl Channel for the DL-SCH.

As shown in Table 1, different types of overhead information may be senton different channels. Table 2 lists some types of overhead informationand provides a short description for each type. Table 2 also gives thechannel(s) on which each type of overhead information may be sent, inaccordance with one design.

TABLE 2 Overhead Information Channel Description System D-BCHInformation pertinent for communicating Information and PBCH with and/orreceiving data from the system. Scheduling MSCH Information indicatingwhen and possibly Information where and how different services are sent.Configuration MCCH Information used to receive the services, Informatione.g., for bearer configurations such as traffic class, RLCconfigurations, lower layer settings, etc. Control PDCCH Informationused to receive transmissions Information or MSCH of data for theservices, e.g., resource assignments, modulation and coding schemes,etc.

The different types of overhead information may also be referred to byother names. The scheduling and control information may be dynamicwhereas the system and configuration information may be semi-static.

The system may support multiple operational modes for E-MBMS, which mayinclude a multi-cell mode and a single-cell mode. The multi-cell modemay have the following characteristics:

-   -   Content for broadcast or multicast services is transmitted        synchronously across multiple cells,    -   Radio resources for broadcast and multicast services are        allocated by an MBMS Coordinating Entity (MCE), which may be        logically located above the Node Bs,    -   Content for broadcast and multicast services is mapped on the        MCH at a Node B, and    -   Time division multiplexing (e.g., at subframe level) of data for        broadcast, multicast, and unicast services.

The single-cell mode may have the following characteristics:

-   -   Each cell transmits content for broadcast and multicast services        without synchronization with other cells,    -   Radio resources for broadcast and multicast services are        allocated by the Node B,    -   Content for broadcast and multicast services is mapped on the        DL-SCH, and    -   Data for broadcast, multicast, and unicast services may be        multiplexed in any manner allowed by the structure of the        DL-SCH.

In general, E-MBMS services may be supported with the multi-cell mode,the single-cell mode, and/or other modes. The multi-cell mode may beused for E-MBMS multicast/broadcast single frequency network (MBSFN)transmission, which may allow a UE to combine signals received frommultiple cells in order to improve reception performance.

FIG. 3 shows example transmissions of E-MBMS and unicast services by Mcells 1 through M in the multi-cell mode, where M may be any integervalue. For each cell, the horizontal axis may represent time, and thevertical axis may represent frequency. In one design of E-MBMS, which isassumed for much of the description below, the transmission time linefor each cell may be partitioned into time units of subframes. In otherdesigns of E-MBMS, the transmission time line for each cell may bepartitioned into time units of other durations. In general, a time unitmay correspond to a subframe, a slot, a symbol period, multiple symbolperiods, multiple slots, multiple subframes, etc.

In the example shown in FIG. 3, the M cells transmit three E-MBMSservices 1, 2 and 3. All M cells transmit E-MBMS service 1 in subframes1 and 3, E-MBMS service 2 in subframe 4, and E-MBMS service 3 insubframes 7 and 8. The M cells transmit the same content for each of thethree E-MBMS services. Each cell may transmit its own unicast service insubframes 2, 5 and 6. The M cells may transmit different contents fortheir unicast services.

FIG. 4 shows example transmissions of E-MBMS and unicast services by Mcells in the single-cell mode. For each cell, the horizontal axis mayrepresent time, and the vertical axis may represent frequency. In theexample shown in FIG. 4, the M cells transmit three E-MBMS services 1, 2and 3. Cell 1 transmits E-MBMS service 1 in two time frequency blocks410 and 412, E-MBMS service 2 (denoted as “S 2”) in a time frequencyblock 414, and E-MBMS service 3 in two time frequency blocks 416 and418. Each remaining cell transmits E-MBMS service 1 in two timefrequency blocks, E-MBMS service 2 in one time frequency block, andE-MBMS service 3 in two time frequency blocks.

In general, an E-MBMS service may be sent in any number of timefrequency blocks. Each time frequency block may have any dimension andmay cover any number of subcarriers and any number of symbol periods.The size of each time frequency block may be dependent on the amount ofdata to send and possibly other factors. The M cells may transmit thethree E-MBMS services 1, 2 and 3 in time frequency blocks that may notbe aligned in time and frequency, as shown in FIG. 4. Furthermore, the Mcells may transmit the same or different contents for the three E-MBMSservices. Each cell may transmit its own unicast service in remainingtime frequency resources not used for the three E-MBMS services. The Mcells may transmit different contents for their unicast services.

FIGS. 3 and 4 show example designs of transmitting E-MBMS services inthe multi-cell mode and the single-cell mode. E-MBMS services may alsobe transmitted in other manners in the multi-cell and single-cell modes,e.g., using time division multiplexing (TDM), frequency divisionmultiplexing (FDM), some other multiplexing schemes, or any combinationthereof.

In an aspect, scheduling information for E-MBMS services may be sentperiodically on a scheduling channel such as the MSCH. In one design,the MSCH may be mapped to the MCH in the multi-cell mode or the DL-SCHin the single-cell mode. The MSCH may also be mapped to other transportchannels.

In one design, the MSCH may be transmitted periodically in eachscheduling period and may carry scheduling information used to receiveE-MBMS services in that scheduling period. In general, a schedulingperiod may cover any time duration, which may be selected based onvarious factors such as channel switching speed, battery power saving,etc. A UE may change channel in the middle of a scheduling period andmay need to wait until the next scheduling period in order to receivescheduling information for the new channel and then start receiving datafrom this channel. A shorter scheduling period may improve channelswitching speed. Conversely, a longer scheduling period may reduce thenumber of times that the UE need to receive or check the MSCH, which mayreduce battery power consumption of the UE. In one design, thescheduling period may be a superframe, which may be 500 ms, one second,or some other suitable duration. The scheduling period for themulti-cell mode may or may not be equal to the scheduling period for thesingle-cell mode.

In one design, the MSCH may be sent in the first N subframes of eachscheduling period. N may be a fixed value (e.g., specified by astandard) and known a priori by all UEs. Alternatively, N may be aconfigurable value and conveyed in the system information, which may besent on the D-BCH or some other channel. The modulation and coding forthe MSCH may be fixed (e.g., specified by a standard) or may beconfigurable (e.g., conveyed on the D-BCH).

In one design, the MSCH may be sent on all available radio resources inthe first N subframes of a scheduling period. The remaining subframes inthe scheduling period may carry data and/or other information forbroadcast, multicast, and/or unicast services. In another design, theMSCH may be sent on a subset of the radio resources in the first Nsubframes. The radio resources used for the MSCH may be conveyed in thesystem information or the control information or may be made known tothe UEs in other manners. The remaining radio resources in thescheduling period may be used to send data and/or other information forbroadcast, multicast, and/or unicast services.

FIG. 5 shows a design of sending the MSCH in the multi-cell mode. Inthis design, the MSCH is sent in the first N=4 subframes of a schedulingperiod and carries scheduling information for all E-MBMS services in thescheduling period. The MSCH may also carry scheduling information forthe MCCH, which may be considered as an E-MBMS service with regard tothe scheduling information. The MCCH may carry configuration informationfor the E-MBMS services. The configuration information may besemi-static and may convey bearer configurations, mapping of serviceidentifiers (IDs) to logical channel IDs, and/or other parameters (e.g.,modulation and coding) for the E-MBMS services.

The scheduling information may be provided in various formats. In onedesign that is shown in FIG. 5, the scheduling information is subframecentric and conveys which MBMS service (if any) is sent in each subframeof the scheduling period. In the example shown in FIG. 5, the schedulinginformation indicates that subframes 5 and 6 carry the MCCH, subframes 7and 9 carry E-MBMS service 1, subframe 8 carries unicast service,subframe 10 carries E-MBMS service 2, subframes 11 and 12 carry unicastservice, subframes 13 and 14 carry E-MBMS service 3, subframes 15 and 16carry unicast service, etc. The scheduling information may conveysubframes for both E-MBMS and unicast services (as shown in FIG. 5) orsubframes for only E-MBMS services.

In another design, the scheduling information is service centric andconveys which subframes are used for each E-MBMS service. In the exampleshown in FIG. 5, the scheduling information may indicate that the MCCHis sent in subframes 5 and 6, E-MBMS service 1 is sent in subframes 7and 9, E-MBMS service 2 is sent in subframe 10, E-MBMS service 3 is sentin subframes 13 and 14, and unicast service is sent in subframes 8, 11,12, 15 and 16. The scheduling information may also convey the subframesused for the E-MBMS services in other manners.

The MSCH may convey the locations (or subframes) of the E-MBMS services,as described above. In one design, the MSCH may also carry controlinformation used to receive the E-MBMS services. In this design, nocontrol information may be sent in the subframes used for E-MBMSservices. In another design, control information used to receive theE-MBMS services may be sent in the subframes in which these services aresent.

Each E-MBMS service may be associated with a service ID and may be senton a logical channel. The mapping of E-MBMS service IDs to logicalchannel IDs may be performed by higher layers and provided, e.g., in aservice guide or some other upper-layer signaling. Theservice-to-channel mapping may be sent in a broadcast or unicast mannerto the UEs. In one design, the scheduling information may convey thesubframes used for different logical channel IDs. The UEs may obtain theservice-to-channel mapping, determine the logical channel IDs for E-MBMSservices of interest, and determine the subframes used for these logicalchannel IDs from the scheduling information. In another design, thescheduling information may convey the subframes used for differentservice IDs, without the need for an intermediate mapping to be signaledexplicitly.

In one design, the number of subframes (N), the modulation and codingscheme, and other parameters for the MSCH may be known a priori by theUEs (e.g., specified in a standard). In this design, the UEs may receivethe MSCH in each scheduling period based on the known information forthe MSCH. In another design, the number of subframes, the modulation andcoding scheme, and/or other parameters for the MSCH may be conveyed inthe system information sent on the D-BCH. In this design, the UEs mayfirst receive the system information from the D-BCH, determine pertinentinformation for the MSCH, and receive the MSCH based on this pertinentinformation.

FIG. 6 shows a design of sending the MSCH in the single-cell mode. TheMSCH may be mapped to the DL-SCH, which may in turn be mapped to thePDSCH. The MSCH may be sent in the first N subframes of each schedulingperiod and may occupy only some resource blocks in these N subframes (asshown in FIG. 6) or all available resource blocks in the N subframes. Nmay be a fixed value or may be conveyed in the system information. Inone design, the resource blocks used for the MSCH may be conveyed bycontrol information sent on the PDCCH associated with the PDSCH, asshown in FIG. 6.

In general, any number of MTCHs may be used to carry data for E-MBMSservices, and any number of MCCHs may be used to carry configurationinformation for the E-MBMS services. The data for each E-MBMS servicemay be sent on one MTCH, and the configuration information for eachE-MBMS service may be sent on one MCCH. In one design, the MTCHs andMCCHs for the E-MBMS services may be sent starting in subframe N+1 ofthe scheduling period after the MSCH has been sent, as shown in FIG. 6.The MTCHs and MCCHs may be mapped to the DL-SCH and may be sent in anassortment of resource blocks that may be dispersed throughout thescheduling period. The resource blocks used for the MTCHs and MCCHs maybe conveyed in several manners. In the design shown in FIG. 6, theresource blocks for the MTCHs and MCCHs may be conveyed by thescheduling information sent on the MSCH. In this design, the schedulinginformation comprises control information, and the MSCH may effectivelyfunction as a collected PDCCH for all resource blocks carrying MBMSservices in the scheduling period. The resource blocks for the E-MBMSservices utilize PDCCH-less transmission, which means that no controlinformation is sent on the PDCCH for these resource blocks.

In the example shown in FIG. 6, a PDCCH transmission 610 may providecontrol information (e.g., resource block assignment and/or otherparameters) for an MSCH transmission 612. MSCH transmission 612 mayprovide scheduling information (e.g., control information such asresource block assignments and/or other parameters) for an MCCHtransmission 614 and MTCH transmissions 616 and 618 for E-MBMS service1. A PDCCH transmission 620 may provide control information for an MSCHtransmission 622. MSCH transmission 622 may provide schedulinginformation for an MTCH transmission 624 for E-MBMS service 2 and MTCHtransmissions 626 and 628 for E-MBMS service 3. The MSCH transmissionsmay be for a single MSCH or different MSCHs. Similarly, the PDCCHtransmissions may be for a single PDCCH or different PDCCHs.

FIG. 7 shows another design of sending the MSCH in the single-cell mode.In this design, the MSCH may be sent in the first N subframes of eachscheduling period, and the resource blocks used for the MSCH may beconveyed by the PDCCH. The scheduling information sent on the MSCH mayindicate the subframes in which the MCCH and the E-MBMS services aresent. The PDCCH may be sent in each subframe indicated by the MSCH andmay convey control information (e.g., resource block assignments and/orother parameters) for the MCCH and/or MTCH transmissions sent in thatsubframe. In this design, the MSCH may effectively function as a pointerto the PDCCH transmissions, which in turn point to the resource blocksused for E-MBMS services in the scheduling period.

In the example shown in FIG. 7, a PDCCH transmission 710 may providecontrol information (e.g., resource block assignment and/or otherparameters) for an MSCH transmission 712. MSCH transmission 712 mayprovide scheduling information for PDCCH transmissions for the MCCH andE-MBMS service 1. These PDCCH transmissions may provide controlinformation (e.g., resource block assignments and/or other parameters)for an MCCH transmission 714 and MTCH transmissions 716 and 718 forE-MBMS service 1. A PDCCH transmission 720 may provide controlinformation for an MSCH transmission 722. MSCH transmission 722 mayprovide scheduling information for PDCCH transmissions for E-MBMSservices 2 and 3. These PDCCH transmissions may provide controlinformation for an MTCH transmission 724 for E-MBMS service 2 and MTCHtransmissions 726 and 728 for E-MBMS service 3.

FIGS. 6 and 7 show example transmissions of the MSCH, MCCH and MTCH. Ingeneral, any number of MSCH transmissions may be sent in each schedulingperiod. Any number of MTCH and MCCH transmissions may also be sent ineach scheduling period, and any number of MTCH transmissions may be sentfor each E-MBMS service. Each transmission may occupy a time frequencyblock of any dimension.

A UE may know the number of subframes (N), the modulation and codingscheme, and other parameters for the MSCH or may obtain this informationfrom the D-BCH. The UE may then receive the PDCCH in the N subframes,obtain control information for the MSCH, and receive the MSCH based onthe control information.

For the design shown in FIG. 6, the UE may obtain scheduling informationfrom the MSCH and may receive the MCCH and/or MTCH transmissions ofinterest based on the scheduling information. The scheduling informationmay include control information (e.g., resource block assignments and/orother parameters) normally sent on the PDCCH for the MCCH and/or MTCHtransmissions. The MCCH may carry configuration information (which maybe provided on a per-service basis) used to receive the E-MBMS services.The configuration information may change infrequently, and it may not benecessary to re-read this information for every MTCH transmission.

For the design shown in FIG. 7, the UE may obtain scheduling informationfrom the MSCH and may receive the PDCCH based on the schedulinginformation. In this design, the scheduling information may include aresource block pointer, a subframe index, or some other information tofind the PDCCH. The UE may then process the PDCCH to obtain controlinformation and may receive the MCCH and/or MTCH transmissions based onthe control information.

For both designs in FIGS. 6 and 7, the information for receiving theMCCH and MTCH transmissions may be reduced by constraining thetransmissions of the MCCHs and MTCHs. For example, if the MCCH and MTCHtransmissions are sent in complete subframes (e.g., as shown in FIG. 4),then the MSCH may carry subframe indices for the MCCH and MTCHtransmissions.

The MSCH may be sent at the start of each scheduling period, asdescribed above and shown in FIGS. 5 to 7. The MSCH may also be sentprior to each scheduling period, e.g., in the last N subframes of theprevious scheduling period. In any general, the MTCH may be sentperiodically in each scheduling period and may carry schedulinginformation for that scheduling period and/or a subsequent schedulingperiod.

FIG. 8 shows a design of a process 800 for sending broadcast, multicast,and unicast services in a cellular communication system. Process 800 maybe performed by a Node B (as described below) or some other entity. TheNode B may multiplex data for broadcast and multicast services and datafor unicast services on radio resources available for transmission(block 812). The Node B may also send configuration information used toreceive the broadcast and multicast services, e.g., on one or moreMCCHs. The configuration information may be considered as anotherbroadcast service. The Node B may periodically send schedulinginformation used to determine radio resources carrying the broadcast andmulticast services (block 814). The scheduling information may conveywhere the broadcast and multicast services are sent, e.g., the timeunits or time frequency blocks used for these services. The schedulinginformation may also convey how the broadcast and multicast services aresent, e.g., control information such as modulation and coding used forthe broadcast and multicast services.

In one design of block 812, the Node B may time division multiplex thedata for the broadcast and multicast services and the data for theunicast services, e.g., as shown in FIG. 5. Each broadcast or multicastservice may be sent in at least one time unit. The unicast services maybe sent in time units not used for the broadcast and multicast services.In this design, the scheduling information may convey the time unit(s)used for each broadcast or multicast service.

In another design of block 812, the Node B may map the data for thebroadcast and multicast services to time frequency blocks. The Node Bmay map the data for the unicast services to remaining radio resourcesnot used for the broadcast and multicast services. In one design, thescheduling information may convey at least one time frequency block usedfor each broadcast or multicast service, e.g., as shown in FIG. 6. Inanother design, the scheduling information may convey the location ofcontrol information, and the control information may convey at least onetime frequency block used for each broadcast or multicast service, e.g.,as shown in FIG. 7. For example, the scheduling information may conveythe time units in which the broadcast and multicast services are sent,and the control information in each time unit may convey the timefrequency blocks used for broadcast and multicast services sent in thattime unit.

In one design, the Node B may send the scheduling information on allavailable radio resources in the first N time units of each schedulingperiod, e.g., as shown in FIG. 5. In another design, the Node B may sendthe scheduling information on at least one time frequency block in thefirst N time units of each scheduling period, e.g., as shown in FIGS. 6and 7. In general, the Node B may send the scheduling information ineach scheduling period to convey radio resources used for the broadcastand multicast services in the current and/or subsequent schedulingperiod. The Node B may also periodically send a flag that indicateswhether or not the scheduling information will change in an upcomingscheduling period.

In one design, each broadcast or multicast service may be sent bymultiple cells in at least one time unit, and these cells may besynchronized, e.g., as shown in FIG. 3. In another design, the broadcastand multicast services may be sent by a cell and may be unsynchronizedwith the broadcast and multicast services sent by neighbor cells, e.g.,as shown in FIG. 4.

FIG. 9 shows a design of an apparatus 900 for sending data in a cellularcommunication system. Apparatus 900 includes a module 912 to multiplexdata for broadcast and multicast services and data for unicast serviceson radio resources available for transmission, and a module 914 toperiodically send scheduling information used to determine the radioresources carrying the broadcast and multicast services.

FIG. 10 shows a design of a process 1000 for receiving services in acellular communication system. Process 1000 may be performed by a UE (asdescribed below) or some other entity. The UE may receive schedulinginformation for broadcast and multicast services multiplexed withunicast services (block 1012). The UE may determine radio resources usedfor at least one service among the broadcast and multicast servicesbased on the scheduling information (block 1014). The UE may thenprocess transmissions received on the radio resources to recover datafor the at least one service (block 1016).

The UE may receive scheduling information in a scheduling period, andmay determine the radio resources used for the at least one service inthe scheduling period based on the scheduling information. In onedesign, each service may be sent on all available radio resources in atleast one time unit, and the UE may determine the time unit(s) in whicheach service is sent based on the scheduling information, e.g., as shownin FIG. 5. In another design, each service may be sent in at least onetime frequency block, and the UE may determine the time frequencyblock(s) used for each service based on the scheduling information,e.g., as shown in FIG. 6. In yet another design, each service may besent in at least one time frequency block in at least one time unit. TheUE may determine (i) the time unit(s) in which each service is sentbased on the scheduling information, and (ii) the time frequencyblock(s) used for each service based on control information sent in thetime unit(s), e.g., as shown in FIG. 7.

FIG. 11 shows a design of an apparatus 1100 for receiving data in acellular communication system. Apparatus 1100 includes a module 1112 toreceive scheduling information for broadcast and multicast servicesmultiplexed with unicast services, a module 1114 to determine radioresources used for at least one service among the broadcast andmulticast services based on the scheduling information, and a module1116 to process transmissions received on the radio resources to recoverdata for the at least one service.

The modules in FIGS. 9 and 11 may comprise processors, electronicsdevices, hardware devices, electronics components, logical circuits,memories, etc., or any combination thereof.

A UE may receive the MSCH in each scheduling period and obtainscheduling information used to receive the MBMS services. Theconfigurations of the E-MBMS services may change infrequently. EachE-MBMS service may be sent at a constant bit rate and may be allocatedthe same radio resources from scheduling period to scheduling period.The content of the MSCH may thus change infrequently. In this case, itmay be desirable for the UE to reduce its activity by receiving the MSCHonly when necessary and receiving the E-MBMS service(s) of interest fromthe same resources in each scheduling period.

In another aspect, a mechanism may be used to notify the UEs when thescheduling information on the MSCH changes. In one design, the systeminformation may include an MSCH change indicator flag, which may bereferred to as simply a change flag. This change flag may be set to (i)a first value (e.g., 0) to indicate that the MSCH will not change in anupcoming scheduling period or (ii) a second value (e.g., 1) to indicatethat the MSCH will change in the upcoming scheduling period. The changeflag may be sent at least once per scheduling period. A UE may read thechange flag and determine whether or not to receive the MSCH based onthe value of the change flag.

FIG. 12 shows a design of sending the MSCH change indicator flag. Inthis design, the MSCH is sent at the start of each scheduling period,and the D-BCH is also sent in each scheduling period. The D-BCH maycarry the change flag as part of the system information. In the exampleshown in FIG. 12, the content of the MSCH does not change in schedulingperiods 1, 2 and 3, and the change flag for each of these schedulingperiods may be set to 0. The content of the MSCH changes in schedulingperiod 4, and the change flag for scheduling period 4 (which may be sentin prior scheduling period 3) may be set to 1.

A UE may receive the MSCH in scheduling period 1 and obtain schedulinginformation from the MSCH. The UE may use the scheduling information toreceive E-MBMS services in scheduling period 1 as well as in schedulingperiods 2 and 3 since the change flag is set to 0. The UE may detect thechange flag being set to 1 for scheduling period 4 and may then receivethe MSCH in this scheduling period. The UE may use the schedulinginformation obtained from the MSCH in scheduling period 4 for eachsubsequent scheduling period in which the change flag is set to 0.

In yet another aspect, a value tag may be used to detect for changes inthe part of the system information carrying the MSCH change indicatorflag. The system information may be partitioned into L parts, and eachpart may be sent in a respective message, where in general L may be oneor greater. Each part may be associated with a value tag that mayindicate the version of the information being sent in that part. Thevalue tag for each part may be incremented each time that part changesand may be used by the UEs to determine whether or not they need to readthat part. For example, if a UE last reads version 3 of a particularmessage and observes that the system is now transmitting version 4, thenthe UE may read the message and obtain updated information sent in themessage.

A UE may read the system information periodically in order to havecurrent information. The MSCH change indicator flag may be sent in onepart of the system information, which may be referred to as the flagcarrying part. Whenever the UE receives the flag carrying part, the UEmay store the value tag of this part. The UE may periodically receivethe value tag of the flag carrying part. If the received value tagmatches the stored value tag, then the UE can ascertain that the flagcarrying part, and hence the change flag, has not changed since the UElast reads this part. In this case, the UE does not need to read theflag carrying part and in particular does not need to read the changeflag. If the value tag has changed, e.g., during scheduling period 3,then the UE may read the flag carrying part and obtain the change flag.The UE may then read the MSCH if the change flag is set to 1 and mayskip reading the MSCH if the change flag is set to 0.

FIG. 13 shows a design of a process 1300 for sending schedulinginformation in a cellular communication system. Process 1300 may beperformed by a Node B (as described below) or some other entity. TheNode B may periodically send scheduling information for broadcast andmulticast services in each scheduling period (block 1312). The Node Bmay periodically send a flag indicating whether or not the schedulinginformation will change in an upcoming scheduling period (block 1314).The Node B may periodically send the flag in a part of systeminformation associated with a value tag and may update the value tagwhenever this part changes.

FIG. 14 shows a design of an apparatus 1400 for sending schedulinginformation in a cellular communication system. Apparatus 1400 includesa module 1412 to periodically send scheduling information for broadcastand multicast services in each scheduling period, and a module 1414 toperiodically send a flag indicating whether or not the schedulinginformation will change in an upcoming scheduling period.

FIG. 15 shows a design of a process 1500 for receiving schedulinginformation in a cellular communication system. Process 1500 may beperformed by a UE (as described below) or some other entity. The UE mayreceive scheduling information for broadcast and multicast services in afirst scheduling period (block 1512). The UE may receive a flagindicating whether or not the scheduling information will change in asecond scheduling period (block 1514). The UE may receive the schedulinginformation in the second scheduling period if the flag indicates thatthe scheduling information will change (block 1516). The UE may skipreceiving the scheduling information in the second scheduling period ifthe flag indicates that the scheduling information will not change(block 1518).

The UE may receive a part of system information comprising the flag anda value tag. The UE may receive the flag only if the value tag indicatesthat this part of the system information has changed. The UE may receivethe scheduling information in the second scheduling period only if theflag is received and indicates that the scheduling information willchange.

FIG. 16 shows a design of an apparatus 1600 for receiving schedulinginformation in a cellular communication system. Apparatus 1600 includesa module 1612 to receive scheduling information for broadcast andmulticast services in a first scheduling period, a module 1614 toreceive a flag indicating whether or not the scheduling information willchange in a second scheduling period, a module 1616 to receive thescheduling information in the second scheduling period if the flagindicates that the scheduling information will change, and a module 1618to skip receiving the scheduling information in the second schedulingperiod if the flag indicates that the scheduling information will notchange.

The modules in FIGS. 14 and 16 may comprise processors, electronicsdevices, hardware devices, electronics components, logical circuits,memories, etc., or any combination thereof.

FIG. 17 shows a block diagram of a design of Node B 110 and UE 120,which may be one of the Node Bs and one of the UEs in FIG. 1. In thisdesign, Node B 110 is equipped with T antennas 1734 a through 1734 t,and UE 120 is equipped with R antennas 1752 a through 1752 r, where ingeneral T 1 and R 1.

At Node B 110, a transmit processor 1720 may receive data for unicastservices and data for broadcast and/or multicast services from a datasource 1712. Transmit processor 1720 may process the data for eachservice to obtain data symbols. Transmit processor 1720 may also receivescheduling information, configuration information, control information,system information and/or other overhead information from acontroller/processor 1740 and/or a scheduler 1744. Transmit processor1720 may process the received overhead information and provide overheadsymbols. A transmit (TX) multiple-input multiple-output (MIMO) processor1730 may multiplex the data and overhead symbols with pilot symbols,process (e.g., precode) the multiplexed symbols, and provide T outputsymbol streams to T modulators (MOD) 1732 a through 1732 t. Eachmodulator 1732 may process a respective output symbol stream (e.g., forOFDM) to obtain an output sample stream. Each modulator 1732 may furtherprocess (e.g., convert to analog, amplify, filter, and upconvert) theoutput sample stream to obtain a downlink signal. T downlink signalsfrom modulators 1732 a through 1732 t may be transmitted via T antennas1734 a through 1734 t, respectively.

At UE 120, antennas 1752 a through 1752 r may receive the downlinksignals from Node B 110 and provide received signals to demodulators(DEMOD) 1754 a through 1754 r, respectively. Each demodulator 1754 maycondition (e.g., filter, amplify, downconvert, and digitize) arespective received signal to obtain received samples and may furtherprocess the received samples (e.g., for OFDM) to obtain receivedsymbols. A MIMO detector 1760 may receive and process the receivedsymbols from all R demodulators 1754 a through 1754 r and providedetected symbols. A receive processor 1770 may process the detectedsymbols, provide decoded data for UE 120 and/or desired services to adata sink 1772, and provide decoded overhead information to acontroller/processor 1790. In general, the processing by MIMO detector1760 and receive processor 1770 is complementary to the processing by TXMIMO processor 1730 and transmit processor 1720 at Node B 110.

On the uplink, at UE 120, data from a data source 1778 and overheadinformation from a controller/processor 1790 may be processed by atransmit processor 1780, further processed by a TX MIMO processor 1782(if applicable), conditioned by modulators 1754 a through 1754 r, andtransmitted via antennas 1752 a through 1752 r. At Node B 110, theuplink signals from UE 120 may be received by antennas 1734, conditionedby demodulators 1732, detected by a MIMO detector 1736, and processed bya receive processor 1738 to obtain the data and overhead informationtransmitted by UE 120.

Controllers/processors 1740 and 1790 may direct the operation at Node B110 and UE 120, respectively. Controller/processor 1740 may implement ordirect process 800 in FIG. 8, process 1300 in FIG. 13, and/or otherprocesses for the techniques described herein. Controller/processor 1790may implement or direct process 1000 in FIG. 10, process 1500 in FIG.15, and/or other processes for the techniques described herein. Memories1742 and 1792 may store data and program codes for Node B 110 and UE120, respectively. Scheduler 1744 may schedule UEs for downlink and/oruplink transmission, schedule transmission of broadcast and multicastservices, and provide assignments of radio resources for the scheduledUEs and services. Controller/processor 1740 and/or scheduler 1744 maygenerate scheduling information and/or other overhead information forthe broadcast and multicast services.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. (canceled)
 2. A method of sending data in acellular communication system, comprising: multiplexing data for aplurality of different broadcast or multicast services and data forunicast services on radio resources available for transmission; andperiodically sending, for each of a plurality of scheduling periods thateach include a plurality of sub-frames, scheduling information thatindicates allocations of different time frequency blocks to each of theplurality of different broadcast or multicast services that have datafor transmission in a given scheduling period.
 3. The method of claim 2,wherein the different time frequency blocks allocated to the pluralityof different broadcast or multicast services that have data fortransmission in the given scheduling period include different sets ofthe plurality of sub-frames in the given scheduling period.
 4. Themethod of claim 3, wherein the different sets of sub-frames overlap atleast partially.
 5. The method of claim 2, wherein the different timefrequency blocks allocated to the plurality of different broadcast ormulticast services that have data for transmission in the givenscheduling period include different frequencies in the given schedulingperiod.
 6. The method of claim 5, wherein the different frequenciesoverlap at least partially.
 7. A method of receiving data in a cellularcommunication system, comprising: periodically receiving, for each of aplurality of scheduling periods that each include a plurality ofsub-frames, scheduling information that indicates allocations ofdifferent time frequency blocks to each of the plurality of differentbroadcast or multicast services that have data for transmission in agiven scheduling period; selecting at least one of the differentbroadcast or multicast services for at least one of the plurality ofscheduling periods; and monitoring the selected at least one broadcastor multicast service for the at least one scheduling period at itsallocated time frequency block within the at least one schedulingperiod.
 8. The method of claim 7, wherein the different time frequencyblocks allocated to the plurality of different broadcast or multicastservices that have data for transmission in the given scheduling periodinclude different sets of the plurality of sub-frames in the givenscheduling period.
 9. The method of claim 8, wherein the different setsof sub-frames overlap at least partially.
 10. The method of claim 7,wherein the different time frequency blocks allocated to the pluralityof different broadcast or multicast services that have data fortransmission in the given scheduling period include differentfrequencies in the given scheduling period.
 11. The method of claim 10,wherein the different frequencies overlap at least partially.
 12. Anapparatus configured to send data in a cellular communication system,comprising: at least one processor configured to multiplex data for aplurality of different broadcast or multicast services and data forunicast services on radio resources available for transmission; and atleast one antenna that is coupled to the at least one processor and isconfigured to send, for each of a plurality of scheduling periods thateach include a plurality of sub-frames, scheduling information thatindicates allocations of different time frequency blocks to each of theplurality of different broadcast or multicast services that have datafor transmission in a given scheduling period.
 13. The apparatus ofclaim 12, wherein the different time frequency blocks allocated to theplurality of different broadcast or multicast services that have datafor transmission in the given scheduling period include different setsof the plurality of sub-frames in the given scheduling period.
 14. Theapparatus of claim 13, wherein the different sets of sub-frames overlapat least partially.
 15. The apparatus of claim 12, wherein the differenttime frequency blocks allocated to the plurality of different broadcastor multicast services that have data for transmission in the givenscheduling period include different frequencies in the given schedulingperiod.
 16. The apparatus of claim 15, wherein the different frequenciesoverlap at least partially.
 17. An apparatus configured to receive datain a cellular communication system, comprising: at least one processorthat is coupled to at least one antenna and configured to: periodicallyreceive, for each of a plurality of scheduling periods that each includea plurality of sub-frames, scheduling information that indicatesallocations of different time frequency blocks to each of the pluralityof different broadcast or multicast services that have data fortransmission in a given scheduling period; select at least one of thedifferent broadcast or multicast services for at least one of theplurality of scheduling periods; and monitor the selected at least onebroadcast or multicast service for the at least one scheduling period atits allocated time frequency block within the at least one schedulingperiod.
 18. The apparatus of claim 17, wherein the different timefrequency blocks allocated to the plurality of different broadcast ormulticast services that have data for transmission in the givenscheduling period include different sets of the plurality of sub-framesin the given scheduling period.
 19. The apparatus of claim 18, whereinthe different sets of sub-frames overlap at least partially.
 20. Theapparatus of claim 17, wherein the different time frequency blocksallocated to the plurality of different broadcast or multicast servicesthat have data for transmission in the given scheduling period includedifferent frequencies in the given scheduling period.
 21. The apparatusof claim 20, wherein the different frequencies overlap at leastpartially.